Lean Bank 1&2

[Engreps]

I was getting a check engine light. Lean Bank 1&2. Rough idle on cold start up.

Just filled up and now not getting check engine light, and also idled fine.

Any ideas on what going on?

 

[MO Viet Vet]

It would be best to post the codes here because if you ask us we want to try and help with the exact codes to look through. It does sound like the start of a fuel pump delivery problem that some how got better after the fill up. Another thing you will learn about here is to share what year your rig is and engine size. Testing fuel pump pressure is a lot more labor involved on the older rigs than the newer. So, "c'mon man", give with the info!

 

[Engreps]

It would be best to post the codes here because if you ask us we want to try and help with the exact codes to look through. It does sound like the start of a fuel pump delivery problem that some how got better after the fill up. Another thing you will learn about here is to share what year your rig is and engine size. Testing fuel pump pressure is a lot more labor involved on the older rigs than the newer. So, "c'mon man", give with the info!

2000 Tahoe 5.3. New Fuel pump installed 10/20 /14 My code reader say Lean Bank 1& 2 does not give a code..

Thank you for your reply......

 

[MO Viet Vet]

At this point I think it may be the dreaded intake vacuum leak because of it being both banks lean at the same time. It is a well known problem and can be intermittent. If happens again you can use a spray bottle of water and spray around where the intake bolts down and see if the idle changes. If you do the repair there will be lots of threads on here about that and lots of great you tubes out there. Use the FELPRO gasket kit, ONLY, get the new nuts and bolts, replace the knock sensors under the intake while in there and use only AC Delco sensors and use either AC Delco or Dorman wiring harnesses for the sensors and remember, make sure all is real real clean when go back together.

 

[Engreps]

At this point I think it may be the dreaded intake vacuum leak because of it being both banks lean at the same time. It is a well known problem and can be intermittent. If happens again you can use a spray bottle of water and spray around where the intake bolts down and see if the idle changes. If you do the repair there will be lots of threads on here about that and lots of great you tubes out there. Use the FELPRO gasket kit, ONLY, get the new nuts and bolts, replace the knock sensors under the intake while in there and use only AC Delco sensors and use either AC Delco or Dorman wiring harnesses for the sensors and remember, make sure all is real real clean when go back together.

Thank you

I thought it might be the intake, what worries me Is that with a full tank of gas and running it for the past three days, no codes showing...

If it was the intake it wouldn't matter what the fuel level was...

 

[MO Viet Vet]

But keep in mind that the problem is intermittent. Lots of things can cause lean conditions. Poor fuel pressure, vacuum leaks, emissions problems..etc.
Get a fuel gauge and check the fuel pressure at the rail at the injectors. There is a shrader valve hook up for this. You can get a decent kit at Harbor Freight that has the extension that allows for the gauge to be hooked up and snaked out under back of hood and tape to windshield so you can drive and monitor. You want to see pressure when you attach or that would mean you have pressure bleed off after you shut down. Not unusual to have about 4-5 psi bleed down but not down to "0". Se what the pressure is running at idle and when accel. Anywhere between 55-65 psi is ok at idle and then goes up a bit when accel and then settles back a bit when get to a cruise speed. You could also have oxygen sensor problems but is highly suspect when both pop up at the same time. If can go to an auto parts store and get the code numbers that should still be in history unless has been enough key cycles since you saw the light last.

 

[Engreps]

raiderron Thank you for your reply. .. I will check the intake and if it is the problem I will change the knock sensor.. On my repairs that I do I only use GM parts. When I change the fuel pump I bought the pump from GM.
I had hurdy to many horror stories of people using after market pumps and having them last only a few hours or a week. One of my friends changed the fuel pump on his Tahoe five times before he bought a OEM GM pump..

 

[MO Viet Vet]

There are 2 knock sensors. The sensors should be AC Delco but the harnesses can be AC Delco or Dorman. The Dorman harnesses are proven to be top grade.

The gasket kit best is FELPRO. Better than the GM kit.

 

[Engreps]

There are 2 knock sensors. The sensors should be AC Delco but the harnesses can be AC Delco or Dorman. The Dorman harnesses are proven to be top grade.

The gasket kit best is FELPRO. Better than the GM kit.

I will get the felpro

Thanks you for your help..

 

[rockenthebowtie]

Raderron I agree with your diagnostic and repair tips, Engreps I agree with sticking ONLY with GM parts including intake gaskets and knock sener wiring harness

 

[MO Viet Vet]

Raderron I agree with your diagnostic and repair tips, Engreps I agree with sticking ONLY with GM parts including intake gaskets and knock sener wiring harness

Thank you but the Felpro gasket kit is better. IMO

They see what is wrong with OE design and function and make it better.

 

[Engreps]

Thank you but the Felpro gasket kit is better. IMO

They see what is wrong with OE design and function and make it better.

I agree.. From the video I watched the Felpro is superior..

 

[rockenthebowtie]

Well the original ones got you 15 years out of them and I'm sure well over 100k miles and there was also design change from the original gaskets and if I'm a competitor I'm sure i can say whatever i want to sell my product.. let see if you get 15 years and over 100k out of them.. good luck sir

 

[MO Viet Vet]

Well the original ones got you 15 years out of them and I'm sure well over 100k miles and there was also design change from the original gaskets and if I'm a competitor I'm sure i can say whatever i want to sell my product.. let see if you get 15 years and over 100k out of them.. good luck sir

1. We don't know if they are the original ones or if they were replaced what they were replaced with.
2. The GM people can say anything they want about their gaskets too.
3. You are assuming quite a lot.
4. Sounds like you work for GM or a dealership from this and other posts you have made. Not a thing wrong with that.
5. Ran shops for 35 years and saw time and time again that Felpro did a better job in MOST cases with a better design to fix an OE gasket problem.
6. Too many people out there with real world experience, like I bet you have too, that agree with me and feel that Felpro is the way to go.


All is my opinion and I don't sell parts or work for Felpro. I just like to do it once and only once and feel they offer the best way to accomplish that. eace:

 

[rockenthebowtie]

Easy bro.. no need to get all raider fan on me this aint a football game bro. Its a forum to share ideas and help others with their vehicles lol.. just messing with you.. just never seen anyone get so defensive over someone elses post.. therse a way to tell if they are original.. what color is the rubber on the gaskets that came off the vehicle

 

[MO Viet Vet]

Easy bro.. no need to get all raider fan on me this aint a football game bro. Its a forum to share ideas and help others with their vehicles lol.. just messing with you.. just never seen anyone get so defensive over someone elses post.. therse a way to tell if they are original.. what color is the rubber on the gaskets that came off the vehicle

Honestly, I wasn't mad at all, just real good about expressing my opinion and backing it up. Didn't mean to offend if I did. Sorry if I did. That's why I said on #4 that there was nothing wrong with dealer tech opinion or if you work there. There is not. Some of the best tech's I ever met were from dealers. Most of the replacement parts I recommend are from the dealer but in this case, I feel the Felpro set up is best. IMO and no offense taken, I mean it. I like your posts. Very thorough. At my age I say what to check and sometimes you follow right behind me on the same thread with your post and say what else I should have said if I hadn't forgot. All good here!

 

[rockenthebowtie]

I didnt take it bad at all.. I'm real good on my end also.. and I really appreciate your great attitude as well i myself have been in the field for just about 30 years myself from independent shops , operator owner and well you know where now lol.. specializing in electrical and drivability, but do bumper to bumper also. Less line and transmission of the exception of transmission eletrical issuse.. and all up to date with full electric and hybrids.. its a daily challenge i welcome.. helps keep my edge at my age lol

 

[MO Viet Vet]

I didnt take it bad at all.. I'm real good on my end also.. and I really appreciate your great attitude as well i myself have been in the field for just about 30 years myself from independent shops , operator owner and well you know where now lol.. specializing in electrical and drivability, but do bumper to bumper also. Less line and transmission of the exception of transmission eletrical issuse.. and all up to date with full electric and hybrids.. its a daily challenge i welcome.. helps keep my edge at my age lol

Well then looking forward to our combined input to try and help some of these Tahoe owners. I started out as a tech for 10 years and then ran shops for 25 and was always with the small independent shops but knew lots of techs in the industry, both independent and dealer. I started out in K.C., Mo. and moved to Eugene, Or. in 96. Retired from it now after 35 years and have been living at and managing storage facility for almost 4 years. I don't want to go back to a shop because I love what I do but I like to help on the forums to keep my edge. Plus I own a Tahoe and sometimes I need info that I get here or at Tahoe/Yukon forum. Anyways, enough with my rambling. Will talk again. :happy160:

 

[rockenthebowtie]

Like wise kind sir hopefully engreps doesn't get upset that we're getting all mushy on his post lol

 

[MO Viet Vet]

Sometimes ASE's can do that after so many years....LOL!